Water Department Research Articles

A perfect storm: The ramifications of Cape Town’s drought crisis

By 2018, the City of Cape Town (CCT) suffered a third consecutive year of serious drought. This article investigates the chronology of the drought and the various measures imposed by the city council to preserve dwindling water supplies in an effort to stave off the so-called ‘Day Zero’ scenario when its water reserves would apparently dry up. By means of contemporary sources, water governance sources and other relevant documentation, the trajectory of Cape Town’s water crisis and the political ramifications for its citizens is being investigated. Finally, lessons to be learnt from Cape Town’s dealing with its drought crisis, and other cities that found themselves in similar situations, will be discussed. An analysis of the political fallout and blaming of who should be held responsible for Cape Town’s precarious water situation is also presented. It seems that a combination of factors was responsible for the city’s relative unpreparedness in dealing with the drought: the politically fractured nature of South African multi-tiered government agencies and the lack of an integrated government approach to the drought; the CCT mayor’s unclear and negative communication to rate payers and ineffective water-saving proposals; a fallout between the CCT mayor and her political superiors over the effectiveness of her drought management plans; a dysfunctional, bankrupt and inert national Department of Water and Sanitation; and the expectation that the city’s expenditure on water supply schemes could be put on hold simply by saving the existing supply in the belief that it would remain stable.

Technical note: An anomaly in pH data in South Africa’s national water quality monitoring database – implications for future use

The South African national water quality database (Water Management System) houses data records from several environmental monitoring programmes, including the National Chemical Monitoring Programme (NCMP). The NCMP comprises an extensive surface water quality monitoring programme, managed by the Department of Water and Sanitation (DWS). The purpose of this technical note is to alert users to a systematic anomaly recently observed in the pH dataset of the NCMP, reflected in an abrupt increase between pre- and post-1990 data records. Although the cause of the anomaly in pH could not be confirmed with high confidence, an inappropriate acid rinse procedure in pre-1990 analytical methods was identified as the most likely cause, based on available evidence. This was supported by the variation in relative sensitivity when comparing the effect on waters with different buffering capacities, i.e., water with low buffering capacity (represented by total alkalinity < 10 mg/L, as CaCO3) showing the largest anomaly, compared with waters of higher buffering capacity (represented by total alkalinity > 30 mg/L, as CaCO3) showing the smallest anomaly. Historical pH data records in the NCMP (i.e. pre-1990), therefore should be used with caution, especially in more weakly buffered systems. The possibility of reconstructing data using a correction factor derived from detailed statistical analyses of the post-1990 pH characteristics at selected sites is a possible solution that could be investigated in future. A key lesson learnt is the need to be diligent in capturing detailed meta-data on sampling procedures and analytical methods in datasets spanning several generations. Availability of such information is critical in order to provide users with a means of evaluating the suitability and comparability of data records in long-term datasets. The DWS includes such meta-data in the current version of the database, dating from about 1995 onwards.

The Pongola Floodplain, South Africa – Part 1: Two-dimensional hydrodynamic modelling in support of an environmental flows assessment

The Pongola Floodplain in the Makhathini Flats is an area of low topographic relief between the 1973-commissioned Jozini Dam, and the Usuthu River which borders Mozambique. The floodplain system is characterised by a complex mosaic of meandering river channels, levees, and floodplains interspersed with pans (or depressions) and wetlands. The landmark 1982 study of the floodplain, Man and the Pongolo Floodplain, suggested a pattern of flows to ‘maintain the floodplain’ based on socio-ecological criteria. Since 1998, however, annual releases have been primarily targeted at the needs of recession agriculture and inundation of the floodplain in the Ndumu Reserve. No releases have been specifcally aimed at maintaining the floodplain ecosystem and the services it delivers to support the livelihoods of local communities. In 2013, the Department of Water and Sanitation commissioned an Ecological Reserve study of the Usuthu/Mhlatuze Water Management Area, which incorporates the Pongola Floodplain. This paper describes two-dimensional hydrodynamic modelling using RMA2 to inform this flow assessment. Four computational Pongola Floodplain models have been developed since 1979, including cell-based, one- and two-dimensional approaches. The RMA2 model is based on existing topographical, hydrological and hydraulic information, and was calibrated and verifed for the period 2008 to 2010 using water-level data from the local hydrometric monitoring network. Generally, good replications have been achieved in terms of peaks, rising and recession limbs, recession of ponded pan water-levels, and low-flow river stages. The RMA2 modelling represents an advancement of previous hydrodynamic studies of the floodplain and contributes to an improved understanding of its hydraulic behaviour. Model application was for the 15-year period 1990 to 2004, and simulations included naturalised, present management (2014), and 7 potential dam operational scenarios. The results were post-processed for analyses in the DRIFT DSS, described in the companion paper.

Assessment of groundwater quality in the buffer zone of Limpopo National Park, Gaza Province, Southern Mozambique.

Many areas in the Southern African Development Community are data-poor and poorly accessible. Water quality assessment in these areas therefore has to rely on the limited available data, coupled with restricted field sampling. This paper documents the first evaluation of the main geochemical processes and impact of anthropogenic and natural sources of contamination on the groundwater quality of the aquifer system used for domestic and agricultural purposes in Limpopo National Park, Gaza Province, Southern Mozambique. Twenty-five groundwater and surface water samples were collected during two field campaigns, one in October 2016 (the end of the arid period) and the other in March 2017 (the end of the wet period). In the field, the researchers analysed chemical-physical parameters such as temperature, pH and EC. In the laboratory, the major ions (boron, Na+, Ca2+, K+, Mg2+) and anions (Cl-, SO42-, NO3-, HCO3-, CO32-) were determined, and almost all groundwater samples fall into the brackish water category. The B/Cl ratio and δ11B concentrations were then measured to better understand the origin of these brackish waters. The direct relationship between boron and chlorine and δ11B concentrations above 40‰ suggests the presence of fossil water in the aquifer. The groundwater in this area was found to be above the limits stated as desirable by the Department of Water and Sanitation (DWS) and the World Health Organisation for domestic and irrigation purposes. The suitability of the groundwater for drinking purposes was also evaluated, with the results indicating that it is not suitable. The values of the sodium absorption ratio, sodium percentage and electrical conductivity show that most of the groundwater samples are also not suitable for agricultural purposes. However, the surface waters have higher quality for both domestic and irrigation purposes. The water of Massingir Lake turns out to be the most suitable resource for a possible rural development plan for the area.

Water, Infrastructure and Power: Contention and Resistance in Post‐colonial Cities of the South

Water, Infrastructure and Power: Contention and Resistance in Post‐colonial Cities of the South

Lake Sibayi variations in response to climate variability in northern KwaZulu-Natal, South Africa

The South African Weather Services (Durban, RSA), the Department of Water and Sanitation, and USGS for data provision.

Tarifação para equacionar os serviços de saneamento ambiental, na cidade de Sousa, no Estado da Paraíba

O objetivo deste trabalho foi propor um método para calcular e equacionar as tarifas para os serviços de saneamento ambiental do Departamento de Água, Esgoto e Saneamento Ambiental (DAESA) da cidade de Sousa-PB, utilizando uma abordagem contábil-financeira. Adotou o método dedutivo, é classificada como exploratória, descritiva e do tipo documental, apresenta um estudo de caso e utilizou uma abordagem quantitativa. Com base nos dados apresentados pelo DAESA: consumo mensal, custos operacionais, número de ligações de abastecimento por tipo de usuário e ligações de esgotamento sanitário, entre outros, foi adotada uma análise considerando o custo-volume-lucro, referente à contabilidade de custos, de forma que essa metodologia pudesse fornecer base para atualização das tarifas existentes, por meio de correções percentuais sobre as mesmas. Para atender ao Ponto de equilíbrio econômico (PEE$) calculado os valores deveriam ser ajustados em 74,9% gerando uma receita de R$ 555.397,81, para cobrir R$ 82.335,40 de custos e despesas fixas e a amortização no valor de R$ 261.258,16, que foi o valor médio mensal da dívida, considerando os cinco últimos anos das faturas emitidas da Companhia de Água e Esgotos da Paraíba (CAGEPA) contra o DAESA. Por fim, descobriu-se ser necessário aproximadamente doze anos, transferindo esse valor amortizado, em parcelas iguais, para pagamento de água tratada pela CAGEPA. É importante afirmar que embora as limitações quanto à coleta das informações, há possibilidade de importar a proposta ao DAESA, corrigindo as atuais falhas quanto à sustentabilidade econômico-financeira.

Using Historical LCR and Water Quality Data to Evaluate Corrosion Control Treatment

Historical Lead and Copper Rule (LCR) regulatory sampling data from the Philadelphia Water Department were examined to explore their potential value for guiding a water utility's progress with regard to optimal corrosion control treatment (OCCT). If a system has established a stable water treatment process with consistent corrosion control treatment (CCT) and has achieved continued decreases in lead levels during regulatory sampling, then the information collected during LCR monitoring can be used as an important data set of a broader OCCT evaluation and will help inform the benefit of additional changes in CCT. Since water utilities have LCR data dating back to 1992, these data should be used to make informed decisions. This research also showed that the addition of orthophosphate has resulted in a significant decrease in lead levels at the customer tap. Additionally, profile sampling was performed to show that first‐draw 1 L samples following a 6 h stagnation period provide a good representation of the lead concentrations measured from lead service line and home plumbing samples at the same sites and may be used to indicate overall changes in lead concentrations at the tap resulting from CCT for this system.

Effects of decomposed poultry litter, nitrogen and phosphorus on growth and micronutrient content of arum (Colocasia esculentus L.)

A pot experiment was carried out to evaluate the integrated effects of poultry litter, nitrogen and phosphorus on the growth and micronutrient (Fe, Zn and Cu) contents of arum (Colocasia esculenta L.) in the net house of the Department of Soil, Water and Environment, University of Dhaka. Height (76 cm), leaf number (5 no./plant), leaf area (1045.66 cm2/plant) and fresh (130.7 g/plant) and dry (14.35 g/plant) weights of leaf, stem, bulb and root were achieved highest in the combined application of decomposed poultry litter compost and nitrogen (PL2N40P0). The leaf area, and fresh and dry weights of leaf, stem, bulb and root varied significantly (p≤ 0.5). The concentration of iron, zinc and copper in different parts were measured the highest in the treatments (0.70%), (0.58%), (0.22%) for leaf; (0.83%), (0.96%), (0.99%) for stem; (0.74%), (0.09%), (0.05%) for bulb and (0.98%), (0.64%), (0.27%) for root, respectively. Generally, the concentrations of Fe, Zn and Cu were found to be the highest in PL4N20P15, PL4N0P15 and PL2N0P0 treatments, respectively.J. Biodivers. Conserv. Bioresour. Manag. 2018, 4(1): 11-18

"I think that's all a lie…I think It's genocide": Applying a Critical Race Praxis to Youth Perceptions of Flint Water Contamination.

In April 2014, the emergency manager of Flint, Michigan switched the city's water supplier from Detroit's water department to the Flint River. The change in water source resulted in the Flint Water Crisis (FWC) in which lead (Pb) from the city's network of old pipes leached into residents' tap water. Residents of Flint reported concerns about the water to officials; however, the concerns were ignored for more than a year. This study sought to understand how Black youth in Flint conceptualize, interpret, and respond to racism they perceive as part of the normal bureaucracy contributing to the FWC. In 2016, we conducted four community forums with Flint youth aged 13 to 17 years. Sixty-eight youth participated with 93% self-identifying as Black. Participants completed a brief survey. We audio-recorded the forums and transcribed them verbatim. Critical Race Theory (CRT) guided the development of the interview protocol and Public Health Critical Race Praxis (PHCRP) served as an interpretive framework during qualitative data analysis. Content analyses were completed using software. Many youth viewed the FWC through a racially conscious frame. They described Flint as a Black city where historical and contemporary forms of racial stratification persist. Some described the contamination of the city's water as a form of genocide targeting Blacks. The findings from this exploratory study suggest some Black youth in Flint have difficulty coping with the FWC. Those who perceive it through a racial frame attribute the crisis to racism. They feel distressed about this and other traumas (eg, failure to address high rates of crime) they perceived as racism-related. Future research should examine the implications for specific mental health outcomes among youth.

Philadelphia Water Department to Revamp Wastewater Laboratories

AbstractThe Philadelphia Water Department recently evaluated laboratory facility improvements and upgrades at its three wastewater plants to enhance current and future services.

A review of groundwater vulnerability assessment in Kenya

Groundwater represents 95% of the world’s unfrozen freshwater. The use of groundwater has significantly increased over the past 50 years and is expected to rise in future due to its high reliability during drought seasons, good quality, generally modest development costs and continuous depletion of surface water. Groundwater pollution is becoming a major threat to fresh groundwater availability and sustainability. The deteriorating groundwater quality and increasing contamination poses detrimental risk to human health and ecosystem in many ways, thereby necessitating the need to study the groundwater vulnerability assessment as a preventive strategy to protect the groundwater from surface pollution. The concept of groundwater vulnerability assessment is dated back in 1970s and applied in many developed countries as an environmental tool used for proper land use planning and decision making without jeopardizing groundwater quality. This paper is a detail review of available literature on the study of groundwater vulnerability assessment in Kenya. The paper revealed that, the vulnerability assessment concept has not been applied as a mechanism to prevent groundwater pollution, hence rarely used in guiding land use planning in Kenya. This review brings to limelight the importance of groundwater vulnerability assessment in management and protection of groundwater resources in Kenya.*Corresponding author; Email:guyesa2016@gmail.com Mobile: 0710953283.1. Soil, Water and Environmental Engineering Department Jomo Kenyatta University of Agriculture and Technology, Kenya

Agricultural economic losses caused by protection of the ecological basic flow of rivers

Equitable distribution of agricultural and ecological water is a great challenge, which has important implications for food safety, with models required to calculate agricultural economic losses caused through protection of the ecological basic flow of rivers. A new model has been used to calculate agricultural economic losses caused by river ecological basic flow in the Baoji Section of the Weihe River, which is the largest tributary of the Yellow River, China. Results show that agricultural economic losses were negatively correlated to high levels of water runoff, with the agricultural water sector often unable to safeguard river ecological basic flow systems when annual food safety guarantee levels of 400 kg per person were met. Water-saving measures could be used to help protect river ecological basic flow, based on policies of agricultural ecological compensation, water rights transactions and encouraging the public to employ appropriate water-saving measures. However, whilst recommendations from this study enabled the agricultural water department to decrease economic losses and improve food safety guarantee levels, they could not provide full protection of river ecological basic flow.

Pollution Plume Development in the Primary Aquifer at the Atlantis Historical Solid Waste Disposal Site, South Africa

The monitoring of pollution plumes from municipal landfills is essential in order to control and, where necessary, remediate aquifer contamination. The Atlantis historical landfill was established in 1975 and was unlined as it preceded the promulgation of the Minimum Requirements by the Department of Water and Sanitation. As the underlying, unconfined sandy aquifer serves as a water supply source to the town of Atlantis, regular quarterly hydrochemical monitoring was carried out from 1989 to 1997, at irregular intervals until 2003, and resumed in 2015 when new, deep boreholes were drilled. Groundwater monitoring over nearly three decades provided valuable information on the nature of the chemical reactions that take place in the subsurface and the extent of transport of chemical constituents. Ammonium and organic carbon, which are subject to redox reactions, were lagging compared to chloride and sodium, which are transported advectively. The most recent data indicated the plume consisted mainly of salinity (electrical conductivity (EC) > 200 mS m−1) in the form of sodium, calcium, chloride and bicarbonate ions 350–400 m down-gradient of the landfill, and it is still expanding at a maximum rate of about 25 m a−1, with local deviations from the regional flow pattern. It also became evident that the plume migrated to greater depth as it was transported further from the waste pile. The breakthrough of contaminants being observed at different depths highlights the importance of suitably designed monitoring networks.

Creating GIS-Based Planning Tools to Promote Equity Through Green Infrastructure

The Philadelphia Water Department, now known as Philadelphia Water (PW), has been coordinating with other city and private and non-profit stakeholders to install green infrastructure (GI) across the city as a means of addressing stormwater runoff as well as promoting social, economic, and environmental benefits such as improved health, job creation, and carbon sequestration. While many planning tools exist to assist in the development of green infrastructure projects, recent critiques have highlighted limitations in their considerations of non-environmental concerns, and several new planning tools have been proposed that use indexes and other need-based approaches to account for a wider range of potential program impacts. Even these new ideas, however, fail to systematically account for the possibility that not only desired GI benefits but also the impacts of specific GI projects may vary considerably from place to place. Based on our experiences with a community advisory board working to assess co-benefits of GI, we propose the inclusion of more interactive methods for incorporating community perspectives on the benefits of GI into GI planning methodologies to make them both more equitable and more responsive to community needs.

Management of Winery Wastewater by Re-using it for Crop Irrigation - A Review

In South Africa, grapes are an important crop in the Western and Northern Cape Provinces. The wine industry makes a significant contribution to the economy in these regions. Wineries generate large volumes of poor quality wastewater, particularly during harvest. Information on actual amounts of water used by wineries is limited and appears to be inconsistent. Usually most of the raw water entering wineries ends up as wastewater. Winery wastewater has high levels of chemical oxygen demand (COD) and contains high levels of K + and Na + . There is considerable variation in wastewater quality parameters between wineries, as well as a strong seasonal variation. In most cases, the wastewater is used for irrigation of small permanent pasture grazing paddocks. The use of winery wastewater for vineyard irrigation could have many potential benefits for the wine industry. Irrigation with wastewaters containing high levels of K + could be beneficial to soil fertility, although long-term application could have negative effects on soil chemical properties. In terms of South African guidelines, wineries must register their intended wastewater use with the Department of Water and Sanitation. The quantity of wastewater irrigated on a weekly basis has to be monitored and wastewater quality measured monthly. Weekly water balances should be drawn up with the assistance of a soil scientist. When selecting crops for irrigation with winery wastewater, soil characteristics and climatic conditions as well as wastewater quality and quantity should be considered. It is important to quantify soil chemical responses to application of winery wastewater every three months.

Maclay Highline Makeover

Looking to accommodate excess flows from the Los Angeles Aqueduct, the Los Angeles Department of Water and Power turned to the Maclay Highline, a dormant system once used to convey water from the aqueduct to the outer reaches of Los Angeles. After an inspection discovered significant damage to the system, the department conducted extensive repairs to enable the Maclay Highline to be returned to service when needed.

Going Beyond Zip Code: Can a Person's Address Help Us Improve Their Acute Care?

Going Beyond Zip Code: Can a Person's Address Help Us Improve Their Acute Care?

Hydrograph separation using tracers and digital filters to quantify runoff components in a semi‐arid mesoscale catchment

AbstractChemical hydrograph separation using electrical conductivity and digital filters is applied to quantify runoff components in the 1,640 km2 semi‐arid Kaap River catchment and its subcatchments in South Africa. A rich data set of weekly to monthly water quality data ranging from 1978 to 2012 (450 to 940 samples per site) was analysed at 4 sampling locations in the catchment. The data were routinely collected by South Africa's national Department of Water and Sanitation, using standard sampling procedures. Chemical hydrograph separation using electrical conductivity (EC) as a tracer was used as reference and a recursive digital filter was then calibrated for the catchment. Results of the two‐component hydrograph separation indicate the dominance of baseflow in the low flow regime, with a contribution of about 90% of total flow; however, during the wet season, baseflow accounts for 50% of total flow. The digital filter parameters were very sensitive and required calibration, using chemical hydrograph separation as a reference. Calibrated baseflow estimates ranged from 40% of total flow at the catchment outlet to 70% in the tributaries. The study demonstrates that routinely monitored water quality data, especially EC, can be used as a meaningful tracer, which could also aid in the calibration of a digital filter method and reduce uncertainty of estimated flow components. This information enhances our understanding of how baseflow is generated and contributed to streamflow throughout the year, which can aid in quantification of environmental flows, as well as to better parameterize hydrological models used for water resources planning and management. Baseflow estimates can also be useful for groundwater and water quality management.

Transforming the Rural Agricultural Landscape Through Groundwater Optimisation: Exploring A Chinese-South African Partnership

The majority of the South African rural populace is directly or indirectly engaged in agricultural practices to earn a livelihood. However, impediments such as climate change, water shortages, and inadequacy of institutional support have undermined these once thriving subsistence farming communities. Furthermore, poor leadership in hydrology, coupled with a lack of depth in skills at all government levels to facilitate the understanding of the importance of groundwater, has made it near impossible for subsistence farmers to benefit optimally from groundwater. The 2012 drought experienced in South Africa paralysed several subsistence farming communities in KwaZulu-Natal. To revamp subsistence farming and assist these farmers across South Africa, the Department of Water and Sanitation launched interventions, but despite the enormous resources expended, indicators (e.g. unsustainable farming practices, poor crop yield, pitiable living conditions, and poor standards of living) provide evidence that these interventions have not yielded the desired results. This paper seeks to suggest practicable interventions aimed at reducing the vulnerability of subsistence farmers in KwaZulu-Natal. The study pursued a qualitative approach in that it solicited the views of experts on groundwater and in related fields to gain an in-depth perspective. Some of the core challenges undermining the sustainability and growth of subsistence farming in the study area were found to be the inadequacy of experts on groundwater, water shortages, institutional deficiencies, lack of political will, and lack of coordination among stakeholders. Pragmatic recommendations are made to address these challenges, among other things to encourage a South African-Chinese partnership in the hydrology sector.